Due to an alleged involvement in an international steroid trafficking network, SIS earned a spot on the US Treasury's List of Specially Designated Nationals.

Apple allegedly paid SIS 47 times over the course of two years after the two companies entered into an app development agreement, according to the Wall Street Journal.

"Specifically, from on or about February 24, 2015 to on or about May 9, 2017, Apple hosted, sold, and facilitated the transfer of SIS's software applications and associated content," the US Treasury Department said in a statement.

The US Department of the Treasury's Office of Foreign Assets Control (OFAC) determined that Apple voluntarily disclosed the apparent violations, and that the apparent violations constitute a non-egregious case.

"In 2017, we found that we had inadvertently paid a developer on (the) U.S. Treasury's List of Specially Designated Nationals," an Apple spokesman was quoted as saying by Apple Insider.

"We reported it to the authorities and fully cooperated with their investigation, which has now been completed," the spokesman added.

The slip-up occurred when Apple's system had listed Stjepanovic's company as "SIS DOO," rather than "SIS d.o.o," as it read on the US Office of Foreign Assets Control list, according to the agreement, said the report.